Readout device



A. E. LINDEN READOUT DEVICE Aug. 2, 1960 Filed Sept. 26, 1958 w 4/ MW 3 5 5 E W; m u m U l I w mp yy F F o L m a m 2%? I 2 F v (I c F a .w 3 O f I, 3) F F m 4 f W E. F .r

BANKI ISL INVENTOR. ALBERT E. LINDEN A770 NE )4 nite States 2,947,911 READOUT DEVICE Albert E. Linden, -Plain'view, N. Y., assignor to American BoschArnra'Corporation, a corporation of New York The present invention relates to electronic computing machines and has particular reference to readout devices therefor.

According to the present invention many readouts of either total count or time may be derived from a single recycling count chain. Banks of glow discharge tubes, such as neon filled bulbs, are triggered on and off by the output flip-flops and at the desired instant of a readout a single bank of the neon lamps is switched from the firing voltage of the flip-flop to a glow discharge sustaining voltage. The sustaining voltage will keep those neon lamps lit that were lit at the time of transition, but will not ignite those lamps which were not lit.

In this way a great many read outs canbe obtained from a single count chain by using as many banks of neon lamps as are desired with a resultant saving of duplicate count chains.

For a more complete understanding of this invention reference may be had to the accompanying diagram, Fig. l, which schematically illustrates the present invention.

In Figure 1 a plurality of bi-stable circuits 20, 30, 40 are connected in a manner such as to form a multistage counter commonly found in binary computing devices. Such counters are useful in counting the total number of pulses arriving at the input terminal 50 over a given interval of time. The number of pulses may indicate the elapsed time, for example. (Alternatively, the total count of pulses may represent constants which are stored or determined elsewhere in the computer and which are to be read out at certain predetermined instants of time.) The bi-stable circuits 10, 20, 30, 40 are conventionally termed flip-flop circuits and may be such as that shown in Fig. 6.24 on page 231 of Automatic Digital Computers by M. V. Wilkes, published in 1956 by John Wiley & Sons, Inc., for example, although they need not be limited thereto.

In Figure 1, the output of flip-flop 10 represents the first digit of the binary number which indicates, for example, the elapsed time; the output of flip-flopZU represents the second digit and so on.

Associated with each flip-flop circuit is a plurality of glow discharge tubes such as neon lamps 11a, 11b, 110, 21a, 21b, 21c and so on, one side of each tube being connected to a common terminal 51, such as ground, and the other side of each lamp being connected to the respective movable arm 12a, 12b, 120, 22a, 22b and 22 of the corresponding shorting type selector switch a, 15b, 150, a, 25b or 250. The left hand stationary contacts 13a, 13b and 130 of switches 15a, 15b, 150 are each connected to the output of flip-flop 10; the left hand stationary contacts 23a, 23b and 2.30 of switches 25a, 25b and 25c are each connected to the output of flipflop 20. Similarly the flip-flop output is connected to neon lamps 31a, 31b and 310 through switches 35a,

atent 35b and 350 and the output of flip-flop 40 is connected to .2 neon lamps 41a, 41 1; and 410 through "switches 45a, 45b and 450. V

The right hand stationary contacts 14a, 14b, 146, 24a, 24b, 24c, etc. of all the selector switches are "connected to the high potential side of a voltage source 52. The voltage of the source 52 is sufficiently high to maintain the glow discharge in the lamps once they have been fired by a higher voltage, but it is not high enough to ignite a lamp by itself. Diodes "16a, -26a, 36a, etc. are interposed in each of "the connections between the right hand stationary contacts of the selectorswitches and the voltage source 52.

The movable contacts such as 12a, for example, are shorting type cont-actswhere both the right hand and left hand stationary contacts such as 13a and 14a are both momentarily connected to contact 12a as the contact 12a is operated from one position to the other.

.:'In operation, it is' required "that at certain predetermined instants "of time't he signal at input 50 be retained for some period of time. .In prior devices a plurality of flip-flops was required, onefor each desired instant, with its own readout device. The present invention removes the necessity for duplicating the flip-flops and uses merely one set of flip-flops witha plurality of readout devices actuated to retain each reading at the desired instant.

Prior to operation, all of the armatures 53, 54 and 55 are initially positioned to the left in Fig. 1 so that the movable contact of each switch is connected to its respective left hand contact, and therethrough to the respective flip-flop output. 4

Each of the lamps 11a, 21a, 31a and 41a which is connected to a flip-flop having an output corresponding to the digit, one will be lit and the others will be dark, the outputs of the flip-flops being sufiicient to ignite the lamps. Obviously, the lamps in each of the other banks b, c, connected to any one flip-flop will have the same condition as the lamp in the a bank.

At the instant the first reading is desired, the armature 53 is operated to the right in Fig. 1 removing lamps 11a, 21a, 31a, 41a from the influence of the flip-flops and connecting them to the constant voltage of supply 52. The condition of each lamp is maintained by the voltage supply 52 as the transfer from the flip-flops to the constant voltage supply is made through the make-beforebreak switches. Thus, the lamps which were lit, remain lit, but the ones which were dark are not lit by the sustaining voltage of supply 52. The diodes 16a, 26a, 36a prevent the flip-flop voltages from igniting glow lamps other than the proper ones through the electrical connections which would exist between the right hand stationary contacts of all the switches in the absence of the diodes.

Similarly at the second instant, the armature 54 is operated to the right, and at the third instant the armature 55 is operated to the right to preserve the instantaneous output of flip-flops 10, 20, 30, 40 on the corresponding bank of lamps b or 0. Here again, the diodes prevent ignition of any of the dark glow lamps of the a bank, as well as any in the b bank itself, as the momentary shorting action of switches 15b, 25b and 35!; occurs. 7

The armatures 53, 54 and 55 may be operated by any means, and specific devices are not enumerated here. Although Fig. 1 shows provision for taking three readings of a four digit number, it should be recognized that any amount of readings may be taken of a number having any amount of digits in the same manner by adding a bank of lamps for each reading and an extra lamp in each bank for each additional digit to be read.

Furthermore, the switching means between the flip-flops and the supply 52 need not be limited to the mechanical construction shown, but such devices as electronic switching, for example, may be used for speed, if desired. The diodes 16a, 16b, 16c, etc. may be omitted if non-shorting type switches having an operating or transition time shorter than the de-ionization time of the glow tubes are used in place of the transfer switches 15a, b, c, and so on.

I claim: V

1. In a device of the character described, a circuit having an output, said output having two discrete voltage levels, a glow discharge tube, a power supply, the

voltage of saidpower supply being less than the ignition voltage but more than the sustaining voltage of said glow tube, and switching means for connecting said glow tube selectively to said output of said circuit or said power supply, said switching means being momentarily connected to both outputs simultaneouslyduring the switching operation. I v v 2. In a device of the character described, a circuit having an output, said output having two discrete voltage levels, a plurality of glow discharge tubes, a power supply, the voltage of said power supply being less than the igniting voltage but more than the sustaining voltage of said glow tubes, and switching means for severally connecting said glow tubes selectively to said out-put of said circuit or said power supply, said switching means 4 being momentarily connected to both outputs simultaneously during the switching operation.

3. In a device of the character described, a plurality of circuits, each circuit having an output and each output having two discrete output voltage levels, a plurality of glow discharge tubes, a power supply, the voltage of said power supply being less than the igniting voltage but more than the sustaining voltage of said glow tubes, said glow tubes being arranged in a symmetrical pattern of banks with one tube in each bank for each of said circuits, switching means connecting to each of said glow tubes for selectively connectingsaid glow tubes to said circuit associated therewith or to said power supply, and means for actuating all of said switching means for each bank simultaneously, said glow tubes being momentarily connected to both said associated circuit and said power supply at the same time during the switching operation.

References Cited in the file of this patent .UNITED STATES PATENTS 2,276,636 White Mar. 17, 1942 2,301,408 Hunt Nov. 10, 1942 r 2,684,440 Wallace July 20, 1954 2,816,251 Grimm Dec. 10, 1957 2,882,451 Daniel Apr. 14, 1959 

